Though four of their bigger stars are off to disappointing first halves this season, the Oakland Athletics are playing good baseball. Once these guys rebound, though, we'll see the difference between good and great.

After nearly three months of baseball, the Athletics are 43-32.

Along the way, there have been plenty of surprises. Josh Donaldson has thrown his name in the hat as an All-Star candidate. Coco Crisp is unleashing unexpected power from the leadoff position. Bartolo Colon is defying the laws of aging.

Unfortunately, not all surprises are good ones.

There's no other way to say it: Jarrod Parker started terribly. Yoenis Cespedes has been injured an alarming amount, and it has hurt his consistency at the plate. Josh Reddick is in the same boat. Brandon Moss is hitting home runs, but that's about it.

Luckily, each of these four players has a chance to turn this season around.

Jarrod Parker

Fantastic news, folks: Parker started the turnaround already.

His ERA has dropped in each of his last 10 starts. On April 30, Parker owned a 7.36 ERA. Now that number is down to 4.30.

In the same stretch, he won six games, lost two and had two no-decisions. Comparing the last 10 to just the last five, his average hits, earned runs allowed and walks per game have gone down while innings pitched have risen.

Young later indicated Parker's slow start might have been caused by an injury, and the subsequent rebound came with a return to health.

He's healthy and rebounding. If Parker continues his current trend, he's going to be as dangerous as he was last year. Even if he comes back down to earth and levels out, he's 6-6 in 90 innings, so 12-12 after 180 isn't awful.

Yoenis Cespedes

Injuries—whether of the half-game variety or those that landed him on the 15-day disabled list—might be to blame for Cespedes' troubles. Then again, of 75 games, he's played in 59 of them.

Three months into the season, though, a .228 average from its biggest superstar is not what Oakland wants to see.

The odd thing is, Cespedes is the team leader in home runs and fourth on the team in slugging percentage. He's also third on the list in RBI, which should tell you he's the Dos Equis version of baseball: He doesn't always get hits, but when he does, they are multi-run home runs.

According to FanGraphs.com, Cespedes strikes out one-quarter of the time while walking less than 10 percent of the time—7.7, to be exact. Additionally, while the year isn't over yet, Cespedes' wins above replacement (WAR) has dropped from 2.9 in 2012 to 1.6 so far.

FanGraphs also shows that Cespedes hits awful with two strikes.

Of course, it's easier said than done to do well with two strikes. But a quick comparison of a random Athletic, Jed Lowrie in this case, shows that he hits nearly 100 points higher than Cespedes in each count (0-2, 1-2, 2-2, 3-2).

Christian Corona of MLB.com reported on June 20 that Cespedes is still nursing a hamstring that has caused him to remain in the designated hitter spot.

Legs are important, especially for a powerful guy like Cespedes. Without that comfortable, healthy lower body, you're going to see a lot more flailing with just the upper arms. And not only is he less than 100 percent, he's not in the field like he would prefer.

The body and psyche are both a bit injured right now.

He's slowly coming around, though. June has been his best month, so if Cespedes continues the upward trend and gets fully healthy, he should finish the season strong.

Brandon Moss

Moss and Cespedes are twins. At least, if you look at their stats side by side, you would think so.

Just like Cespedes, Moss is co-leader in the home runs category and second in RBI. He's also the team leader in strikeouts and is batting just .241.

So again, just like Cespedes, most of his hits are home runs with runners on base.

Moss got hot beginning on April 9 and stayed above .270—at times above .300—until May 6. That's when he slowly started to falter. One month to that date, he was hitting .224.

So far, so good with the adjustments. In the last 10 games, his average has crept up 20 points.

Once Moss gets comfortable again, it shouldn't be expected that he'll suddenly hit .300, but something between his career .249 and last year's .291 is plausible.

Josh Reddick

First, the bad news: Reddick is hitting just over the Mendoza Line after almost half of a season. But here's the good news: His batting average is rising slowly but surely.

Reddick acknowledged his struggles on May 2, according to John Hickey of MercuryNews.com, but said he was working with hitting coach Chili Davis every day.

Then a wrist injury sidelined him four days later, keeping him out 22 games.

It's been a long-lasting stroke of bad luck for Reddick. But now that he has returned to the lineup and is healthy, he is making progress. David Wiers of Fangraphs.com pointed out a few numbers on June 17 that should make fans hopeful.

...over his past 10 games, Reddick has 18 hits in his past 65 plate appearances. Don’t be fooled by his current .211/.302/.340 line as that is just a cruel representation of his early season struggles. Despite the triple slash, Reddick is walking more, striking out less, and swinging less than ever before. His .240 BABIP is still 30 points below his career average and as that continues to climb, so will his triple slash.

Oakland fans hope those numbers continue their upward climb as he gets fully back into the swing of things.

Conclusion

It's a luxury to complain about the two men who score the most runs and put a ton of baseballs over the wall. The other two players are showing signs of bouncing back already, so it's not wild to predict them to turn things around.

Again, Oakland is playing good baseball.

If just one of these guys continues to streak upward, the A's are going to be in great shape. But if all four pick it up?